Dam.



' AUNTED s'rA'rEs PATENT OFFICE.

JOHN FRANCIS GREATHEAD, OF ROME, NEW YORK.

DAM.

Application filed May 2, 1911.

To all whom tt may concem:

Be it known that I, JOHN F. GREATHEAD, a citizen of the United States, and a resident of Rome, in the county of Oneida and State of New York, have invented a new and Improved Dam, of which the following is a full, clear, and exact description.

The invention relates to concrete structures and its object is to provide a new and improved dam arranged to utilize the passive pressure of the ground to hold the dam in position against the water pressure and to prevent seepage of the water underneath the bottom of the dam.

In order to accomplish the clesired result the dam is formed of a monolithic cantaliver structure having an upper portion for the water pressure, and a lower portion built in the ground a distance'suflicient fo-r the passive pressure of the ground on both faces of the lower portion to overcome the overturning tendency of the water pressure on the upper portion.

A practical embodiment of the invention is represented in the accompanying drawings forning a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

F igure 1 is a Vertical section of the dam; Fig. 2 is a like View of a modified form of the dam provided with a non-monolithic apron; Fig. 3 is a similar view of a modi-.

fied form of the dam provided with a monolithic apron; and Fig. 4: is a similar view of a modified form of the dam provided with a monolithic apron, and an upper portion inclined in an upstream direction for a high velocity of approach.

The dam A, illustrated in Fig. 1, is in the form of a monolithic cantaliver structure or slab, preferably of reinforced concrete, and consisting of an upper lever portion B extending across the waterway C, and a lower lever portion D embedded in the ground or embedment E a distance sufiicient for the passive pressure of the ground on both faces of the lower portion D to overcome the overturning tendency of the water pressure against the lip-stream face of the upper portion B.

In case the embedment of the lower portion D of the lever A is sand or earth then the portion extends downward a distance in proportion to 'the upper portion B, as indicated in Fig. 1,' but when the embedment is rock a channel is formed in the rock, say

Specfication of Letters Patent.

Patented Nov. 28, 1911.

Serial No. 624,538.

to a depth indcated by the line a-a, and in this channel extends the lower portion D of the dam. It is understood that the passive pressure of the rock is considerably greater than the passive pressure of sand or earth, and hence the lower portion D must necessarily extend farther down in the ground, if the latter is of sand or earth, than when the embedment is of rock.

In the modified form shown in Fig. 2, the dam A' is similar to the one shown in Fig. l, that is, it consists of an upper portion B' and a lower portion D, of which the upper portion B' extends across the waterway C' and the lower portion D' is embedded in the groun d or bed E On the down stream side of the dam A is arranged a water apron F, preferably made separate from the dam and not necessarily reinforced. The down stream lower end may be provided with a water cut-off F' to prevent water from passing under the apron F, and the lower end may also be provided with drain openings F 2 for draining the apron F.

In the modified form shown in Fig. 3, the dam `A having the portion B and D is provided with a water apron Gr made integral with the dam A and having its bottom inclined inan upward and down-stream direction, the end G' of the apron, extending as a water cut-off into the ground E and having drain openings G It is understood that in this case the pressure of the water in the waterway C against the upper portion B of the dam is resisted by both the lower portion D and the apron G.

In the modified form shown in Fig. &the

upper portion B? of the dam A is inclined upwardly and in an upstream direction across the waterway 0 while the lower portion D of the apron H with its water cutof H' is similar to the corresponding parts shown in Fig. 3, and is provided with drain openings H It is understood that the dams illustrated in Figs. 2 and 3 are more especially designed for a low velocity of approach, while the dam illustrated in Fig. 4 is more especially designed for a high velocity of approach.

It is understood that the upper portion B, B', B or B of the dam varies in shape and inclination according to the use of the dam as a mere reservoir dam or as a spillway, and in the latter case according to the velocity of the approaching water. It is further understood that when the ground --than 90 to keep the Water-sheet against the V downstream face of the spillway.

It will be noticed that by extending the lower portions D, D', D or D down into the ground as described a Very effective seepage cut-off is produced and hence loss of water and undermining is reduced to a minimum, and it will further be noticed that the said lower portions are built in the ground to a depth sufficient, that the pressure of the ground acting normally on both faces of the lower portions overcomes the overturning tendency of the water pressure on the upper portions B, B', B and 13 solely by resistance to bending strains in the body of the structure. The lower ends or crests of the aprons F, Gr and H are raised above the elevation of the ground E, E and E whereby the surface of the water in the apron is above the elevation of the ground. By the arrangement described the fall of the water is reduced and less excavation is required. I

Having thus described my invention, I claim as new and desire to secure by Letters Patent l. A dam, comprising a monolithic cantaliver structure having an upper and a lower portion, the upper portion being exposed to the Water pressure and the lower portion being built in the ground to a depth sufficient that the pressure of the ground acting normally on both faces of the lower portion overcomes the overturning tendency of the water pressure on the said upper portion solely by resistance to bending strains in the body of the said structure.

2. A dam, comprisng a monolithic cantaliver structure having an upper and a lower portion, the upper portion being eX- posed to the water pressure and the lower portion being built in the ground to a depth sufficient that the pressure of the ground on both faces of the lower portion overcomes the overturning tendency of the Water pressure on the said upper portion, and a water apron on the down stream side of the said structure.

3. A dam, comprising a monolithic cantalive' structure having an upper and a lower portion, the upper portion being eXposed to the water pressure and the lower portion being built in the ground to a depth suficient that the pressure of the ground on both faces of the lower portion overcomes the overturning tendency of the water pressure on the said upper portion, and a Water apron integral with the said structure on the down stream side thereof.

4. A dam, comprisng a monolithic cantaliver structure having an upper and a lower portion, the upper portion being eXposed to the water pressure and the lower portion being built in the ground to a depth sufiicient that the pressure of the ground on both faces of the lower portion overcomes the overturning tendency of the water pressure on the said upper portion, and a water apron integral with the said structure on the down stream side thereof, the elevation of the Water surface over the apron being higher than the elevation of the ground.

5. A dam, comprising a monolithic canta- "liver structure, having an upper and a lower portion, the upper portion being eX- posed to the water pressure and the lower portion being built in the ground to a depth suflicient that the pressure of the ground on both faces of the lower portion overcomes the overturning tendency of the Water pressure on the said upper portion, and water apron extending integrally upwardly and in JOHN FRANCIS GREATHEAD.

VVitnesses:

GEORGE H. FRAVER, R. Gr. S. HORLAND.

copies of thispatent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, I). C." 

